Semiconductor Components Industries, LLC

Fairchild Semiconductor Corporation

Sangcheol Moon

Jintae Kim

Hangseok Choi

Cheng-Sung Chen

Taesung Kim

Gwanbon Koo

BongGeun Chung

Chenghao Jin

Dongjin Park

Chi Chen Chung

Chen-Hua Chiu

Inki Park

Chi-Chen Chung

JooHoon Kim

Jihoon Jang

Hybrid control of switching power converters. One example embodiment is a method including: operating the switching power converter such that a charge control switch has a conduction time in each switching cycle; and making adjustments to the conduction time, the adjustments dominated by voltage-mode control when the switching power supply is in a first operational state, and the adjustments dominated by current-mode control when the switching power supply is in a second operational state distinct from the first operational state.

Hybrid control of switching power converters

It may be desirable to limit the switching frequency of a pulse frequency modulated (PFM) resonant converter, however certain load conditions and/or startup condition require high switching frequencies to regulate an output voltage. The disclosed resonant converter can limit a maximum switching frequency while regulating an output voltage by shifting from PFM to phase-difference modulation based on a load condition. The appropriate modulation can be applied based on a comparison between a charge-control signal and a load-control signal.

Resonant converter with dual-mode control

Resonant power converters. Example embodiments are methods of operating a rectification controller including sensing a drain-source voltage of a synchronous rectification (SR) field effect transistor (FET); setting an adaptive delay time corresponding to a time interval between a first state transition and a second state transition, with each of the first and second state transitions corresponding to the drain-source voltage transitioning between being greater than the adaptive delay voltage and being less than the adaptive delay voltage; and driving the SR FET to a conductive state after the drain-source voltage having been less than the on-threshold voltage for longer than the adaptive delay time.

Adaptive SR turn-on control in an LLC resonant converter

A buck converter includes a power switch having a first end to receive an input voltage, a synchronous switch connected between a second end of the power switch and the ground, an inductor having a first end connected to the other end of the power switch, and a switch control circuit configured to turn off the synchronous switch when a zero voltage delay time passes after an inductor current flowing through the inductor reaches a predetermined reference value, calculate a dead time based on the input voltage and the zero voltage delay time, and turn on the power switch when the dead time passes following the turn-off time of the synchronous switch.

Switch control circuit and buck converter comprising the same

A circuit for controlling a power converter includes an SR switching device, a light load detection circuit generating a load detection signal in response to a conduction signal and an operation mode signal, and an SR driver generating a control signal having a value according to the load detection signal and provide the control signal to the SR switching device. A method of controlling a power converter includes generating a load detection signal in response to a conduction signal and an operation mode signal and generating a control signal having a value according to the load detection signal. The control signal has a first value when the load detection signal is asserted and has a second value when the load detection signal is de-asserted.

Adaptive control of synchronous rectifier switching device

A circuit for controlling a power converter includes a transient detector that generates a transient detection signal in response to a feedback signal indicating an output signal of the power converter, a gain selector that generates a gain selection signal in response to the transient detection signal, and an amplifier circuit that generates a comparison signal based on the value of the feedback signal, a value of a reference signal, and a gain value of the amplifier circuit, the gain value being adjusted in response to the gain selection signal. The transient detection signal indicates that a value of the feedback signal is in a first range and a specific condition of the feedback signal is detected.

System and method for controlling voltage control loop in power converter

Provided is a power factor correction circuit including an inductor having one end to which an input voltage is applied; a power switch connected between another end of the inductor and the ground, and configured to control an output of the power factor correction circuit; and a power factor correction controller configured to calculate a duty of the power switch on the basis of an output detection voltage corresponding to the output and an inductor current flowing through the inductor, calculate conduction-period information regarding a conduction period in which the inductor current flows in one switching cycle of the power switch, and compensate the calculated duty on the basis of the conduction-period information.

Power factor correction circuit with calculated duty compensation and driving method thereof

According to an implementation, a resonant converter for short-circuit protection includes an oscillator, a short-circuit detector configured to detect a short-circuit condition in a component of the resonant converter, and a pulse width modulation (PWM) controller configured to control the oscillator in a PWM mode before short-circuit protection is triggered. The oscillator, when in the PWM mode, is configured to generate a first clock signal for driving a first power switch and a second clock signal for driving a second power switch.

Short-circuit protection using pulse width modulation (PWM) for resonant converters

A Power Factor Correction (PFC) circuit includes an oscillator circuit. The oscillator circuit receives a valley detect signal indicating a zero current condition, determines a blanking time according to an operational cycle of the PFC circuit, and determines to initiate the operational cycle according to the valley detect signal and the blanking time. Determining the blanking time includes selecting one of a plurality of predetermined blanking times according to a count of operational cycles of the PFC circuit. The PFC circuit may operate in a Boundary Conduction Mode or a Discontinuous Conduction Mode depending on whether a charge-discharge period is greater than the blanking time. The PFC circuit may determine, according to its output voltage, a first duration of a charging period, determine a delay time according to zero current times of previous operational cycles, and extend the first duration of the charging period by the delay time.

Power factor correction circuit and method

A power converter includes a transformer, a first primary side transistor coupled to the primary winding, a primary side controller that provides a gate signal to a gate of the first primary side transistor, a first synchronous rectifier (SR) transistor, and an SR controller. The first SR transistor has a drain coupled to a secondary winding of the transformer, a gate for receiving a first SR gate signal, and a source coupled to a first output terminal of the power converter. The SR controller is coupled to the gate and drain of the first SR transistor, for activating the first SR gate signal when a voltage on the drain falls below a turn-on threshold, and deactivating the first SR gate signal when a voltage on the drain rises above a variable turn-off threshold, wherein the variable turn-off threshold increases over an expected on-time of the first SR gate signal.

Synchronous rectifier control for switched mode power supplies and method therefor

A Synchronous Rectifier (SR) controller circuit includes a dead time evaluation circuit, an offset voltage controller circuit, an off threshold control circuit, and a comparator circuit. The dead time evaluation circuit produces an indication of whether a measured dead time of an SR switching device is less than a target dead time. The offset voltage controller circuit determines an offset count using the indication, an offset voltage using the offset count, and high and low saturation indicators according to the offset count. The off threshold control circuit determines a threshold count using the high and low saturation indicators and an off threshold voltage using the threshold count. The comparator circuit determines whether a measured voltage of the SR switching device is greater than a virtual off threshold voltage, the virtual off threshold voltage corresponding to the off threshold voltage minus the offset voltage.

Automatic control of synchronous rectifier turn-off threshold

A buck converter includes a power switch having one end to which an input voltage is transferred, a synchronous switch connected between the other end of the power switch and the ground, an inductor having an end connected to the other end of the power switch, and a switch control circuit configured to calculate a zero voltage delay time based on at least an ON time of the power switch and a delay time. The delay time is determined based on the inductor and parasitic capacitors of the power switch and the synchronous switch.

Switch control circuit and buck converter including the same

A circuit comprises an Inductor-Inductor-Capacitor (LLC) tank circuit and an energizing circuit. The LLC tank circuit includes first and second inductors, a capacitor, and a primary coil of a transformer. The first inductor is coupled in series with the second inductor, the second inductor is coupled in series with the capacitor, and the primary coil is coupled in parallel with the second inductor. The energizing circuit supplies power to the LLC tank circuit according to a switching period, and detects a power limit condition according to a value of an integrated current sense signal and a duration of the switching period. The integrated current sense signal corresponds to an integration over time of a current supplied to the LLC tank circuit. The circuit may be incorporated into a power converter to provide power limit detection according to an accurate real-time estimation of the power converter's output power.

Power limit protection for resonant power converter

According to an implementation, a resonant converter for detecting non-zero voltage switching includes an oscillator configured to generate a first clock signal to drive a first power switch, and a second clock signal to drive a second power switch. The resonant converter includes a non-zero voltage switching (non-ZVS) detection circuit configured to receive an integrated current sense signal sensed on a primary side of a transformer of a resonant network, and determine a polarity of a voltage of the integrated current sense signal at a predetermined point in the first clock signal or the second clock signal during a switching cycle. The non-ZVS detection circuit is configured to detect a non-ZVS event based on the polarity of the voltage of the integrated current sense signal at the predetermined point in the first clock signal or the second clock signal during the switching cycle.

Non zero-voltage switching (ZVS) detection in resonant converters

A method for controlling a power converter includes determining whether a value of a feedback signal is in a first range, detecting a plurality of points of the feedback signal, and decreasing one or both of a proportional coefficient and an integral coefficient of a first control loop of the power converter at a first plurality of times corresponding to the detected plurality of points of the feedback signal when the value of the feedback signal is in the first range. The feedback signal indicates an output signal of the power converter. A circuit for controlling a power converter includes a transient detector that generates a transient detection signal in response to a feedback signal indicating an output signal of the power converter and a gain selector that generates a gain selection signal in response to the transient detection signal.

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Bucheon, South Korea

Sangcheol Moon